Fears over hip replacements

Medical regulators have launched an investigation into the safety of metal hip replacements amid fears that thousands of British patients are at risk of being poisoned by the implants.

The Medicines and Healthcare products Regulatory Agency said it had taken "prompt action" over the safety concerns, but added the majority of people with the devices are at "low risk of developing any serious problems".

The action comes as an investigation by The Sunday Telegraph found more than 30,000 British patients have received the "metal-on-metal" (MoM) hip replacements.

Problems occur when friction between the metal ball and cup causes tiny metal filings to break off and potentially enter the blood. These fragments can also cause a soft tissue reaction, destroying muscle and bone.